Kabul - Hundreds of villagers in western Afghanistan demonstrated Saturday to protest the apparent death of scores of civilians in a US airstrike in Herat Province.

Afghan police increased their estimate of the number of civilians killed to more than 90, and the senior UN representative called for a thorough investigation into the incident that took place in the village of Aziz Abad on Friday.

The US military said in a statement that it had launched an investigation. "All allegations of civilian casualties are taken very seriously," the statement said.

Western region police spokesman Abdul Raouf Ahmadi said that more than 90 civilians had been killed in the strike, speaking to Deutsche Presse-Agentur dpa by phone from Aziz Abad.

He said the provincial governor along with other senior Afghan officials visited the remote village in the Shindand district on Saturday morning and saw the bodies of the civilians, most of them children.

Ahmadi said that hundreds of villagers had taken to the streets to throw stones at Afghan troops, despatched to the area to deliver aid to the families who had lost relatives in the bombing.

Three of the protestors were wounded when the troops opened fire to break up the demonstration. The police spokesman said the villagers had turned down the aid and had forced the soldiers to leave.

The Afghan Interior Ministry said Friday that a US-led operation had killed 19 women, seven men and 50 children under the age of 15.

The US military said 30 militants, including a rebel commander, had been killed in the operation, mounted after joint Afghan and coalition forces were ambushed by militants hiding inside compounds in the village.

President Hamid Karzai Saturday condemned the killings and vowed his government would take the measures necessary to prevent such deaths in the future.

Karzai blamed the US-led coalition forces for carrying out the attack without coordinating with the Afghan army.

"All efforts of the Afghan government to avoid civilian casualties have not yielded any positive results and our innocent countrymen are still killed in anti-terrorism operations," Karzai said in a statement.

The president also said his government would take the "necessary measures" to curtail such deadly incidents and would soon announce the details of the plan.

The top representative of the UN Secretary General for Afghanistan, Kai Eide, said it was vital that the incident be investigated thoroughly.

"The United Nations has always made clear that civilian casualties are unacceptable - they undermine the trust and confidence of the Afghan people," Eide said.

UN staff in western region have been instructed to help Afghan authorities verify the facts.

If confirmed, the civilian death toll for Friday's air raid would be the highest since the deployment of foreign forces in the country following the ousting of the Taliban regime in late 2001.

In April 2007, more than 50 civilians were killed in the same district when coalition forces bombed suspected Taliban militants, a UN investigation found.

Civilian casualties during the international operations against the Taliban are a matter concern for the Western-backed Afghan government as it struggles to win legitimacy among the population.

More than 3,000 people - mostly insurgents but including more than 1,000 civilians - have been killed so far this year, according to figures provided by Afghan and international military sources. (dpa)